Thanks for your comments. I'm glad I wrote in. I didn't want to sell the platter until I was convinced I was moving in the right direction.
I'm generally a little suspect of the hype in the industry, and don't always assume that upgrades, even expensive ones, and going to yield significant, audible results in my system.
That being said, I thought I detected some speed variation after I put the old platter back on, and it seems as though there is a consistent opinion that the TNT platter is going to make a difference in this respect, at least.
I'll play it some more, then swap the upgraded platter back on and see what difference it makes.
I just got the TT last Friday, and hadn't had a chance to get VPI's tall cover pricing. $160 is reasonable, and about half what I expected.